Inductive coil assembly

ABSTRACT

An inductive coil assembly having multiple coils arranged at distinct orientations to provide efficient inductive coupling of power or communications or both to a device when the device is arranged at different orientations with respect to the inductive primary coil. In one embodiment, the inductive coil assembly includes three coils, each oriented along one of the x, y and z axes of a standard Cartesian three-dimensional coordinate system. The three separate coils provide effective transfer of power and communication when the device is at essentially any orientation with respect to the primary coil. In an alternative embodiment, the multi-axis inductive coil assembly of the present invention can function as a primary to inductively transmit power or communication or both over a plurality of magnetic fields at distinct orientations.

[0001] The present invention is a continuation-in-part of U.S. patentapplication Ser. No. 10/357,932, entitled “Inductively PoweredApparatus,” which was filed on Feb. 4, 2003.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to the inductive transfer of powerand communications, and more particularly to methods and apparatus forreceiving inductively transmitted power and communications.

[0003] The principles of inductive power transfer have been known formany years. As a result of mutual inductance, power is wirelesslytransferred from a primary coil (or simply “primary”) in a power supplycircuit to a secondary coil (or simply “secondary”) in a secondarycircuit. The secondary circuit is electrically coupled with a device,such as a lamp, a motor, a battery charger or any other device poweredby electricity. The wireless connection provides a number of advantagesover conventional hardwired connections. A wireless connection canreduce the chance of shock and can provide a relatively high level ofelectrical isolation between the power supply circuit and the secondarycircuit. Inductive couplings can also make it easier for a consumer toreplace limited-life components. For example, in the context of lightingdevices, an inductively powered lamp assembly can be easily replacedwithout the need to make direct electrical connections. This not onlymakes the process easier to perform, but also limits the risk ofexposure to electric shock.

[0004] The use of inductive power transfer has, however, for the mostpart been limited to niche applications, such as for connections in wetenvironments. The limited use of inductive power transfer has beenlargely the result of power transfer efficiency concerns. To improve theefficiency of the inductive coupling, it is conventional to carefullydesign the configuration and layout of the primary and secondary coils.The primary and the secondary are conventionally disposed within closelymating components with minimal gap between the primary and thesecondary. For example, the primary is often disposed within a basedefining a central opening and the secondary is often disposed within acylindrical component that fits closely within the central opening ofthe base. This and other conventional constructions are design toprovide close coaxial and radial alignment between the primary coil andthe secondary coil. Several specific examples of patents that reflectthe conventional approach of providing a fixed, predetermined physicalrelationship between the primary and secondary coils include: U.S. Pat.No. 5,264,997 to Hutchisson et al, which discloses an inductive lampwith coaxial and closely interfitting primary and secondary coils; U.S.Pat. No. 5,536,979 to McEachern et al, which discloses an inductivecharging device in which the device to be charged is fitted closelywithin a cradle to position the coils in a fixed, predeterminedrelationship; U.S. Pat. No. 5,949,155 to Tamura et al, which discloses ashaver with adjacent inductive coils set in a fixed relationship; U.S.Pat. No. 5,952,814 to Van Lerberghe, which discloses an inductivecharger for a telephone wherein the physical relationship between theprimary and secondary coils is fixed; and U.S. Pat. No. 6,028,413 toBrockman, which discloses a charging device having a mechanical guidefor ensuring precise, predetermined alignment between the inductivecoils. The conventional practice of providing precise alignment betweenthe primary and secondary coil has placed significant limitation on theoverall design and adaptability of inductively powered devices.

SUMMARY OF THE INVENTION

[0005] The aforementioned problems are overcome by the present inventionwherein a device is provided with an inductive coil assembly having aplurality of secondary coils that are each arranged in a differentorientation. The multiple coils permit the device to efficiently receivepower or communications or both when the device is disposed at differentorientations with respect to the primary.

[0006] In one embodiment, the inductive coil assembly includes threecoils that are arranged along the x, y and z axes of a standardCartesian coordinate system. In this embodiment, efficient power andcommunications transfer is obtainable regardless of the orientation ofthe device within the primary.

[0007] In another embodiment, the inductive coil assembly includes asingle set of coils to receive power and to send and receivecommunications. In this embodiment, the power signal functions as acarrier signal for the communications. In an alternative embodiment,separate coils can be provided for power and communication. For example,a first set of z, y and z coils can be provided to receive power and asecond set of x, y and z coils can be provided to receivecommunications.

[0008] In one embodiment, the inductive coil assembly includes aone-piece bobbin that facilitates manufacture and assembly of theinductive coil assembly. The bobbin includes a separate spool withwinding guides along each of the three axes and is designed to permitmolding without the need for slides, pins or other complex mold tools.

[0009] In another embodiment, the inductive coil assembly can be used asa primary to transmit power or communication or both to a second. Theinductive coil assembly with different coils at different orientationscan generate magnetic fields at different orientation and therebyprovide sufficient inductive coupling when an inductive device with onlya single secondary coil is at different orientations.

[0010] In applications where only a single coil is used, it is possiblethat a device randomly placed within a magnetic field will be locatedwith the coil oriented substantially parallel to the magnetic field. Insuch situations, the secondary may not receive sufficient power to powerthe device from the primary. The use of multiple coils addresses thisproblem by providing a secondary coil arrangement that significantlyincreases the likelihood that at least one coil will at leastsubstantially intersect the flux lines of the magnetic field generatedby the primary. For example, an inductive device may include a secondarywith two coils that are oriented at 90 degrees to one another. With thisconfiguration, at least one of the two coils is likely to extend acrossthe flux lines of the magnetic field and receive power from the primary.The number of separate coils may vary from application to application,for example, the inductive device may include 3, 4, 6 or 8 coils atdifferent orientations to provide improved efficiency in a wide varietyof orientations. By providing a sufficient number of coils at differentorientations, the inductive device can be configured to receive powerfrom the primary regardless of the orientation of the inductive device.

[0011] The present invention provides a simple and inexpensive inductivecoil assembly that improves the efficiency of inductive systems whenprecise primary/secondary alignment does not exist. The presentinvention permits power and communications to be transferred inductivelyin an environment where the position of the secondary within the primarymay vary. The inductive coil assembly is manufactured on a bobbin thatprovides winding guides along all three axes, yet is easily manufacturedwithout complex slide, pins or other complex mold tools.

[0012] These and other objects, advantages, and features of theinvention will be readily understood and appreciated by reference to thedetailed description of the preferred embodiment and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1a is a perspective view of an inductive coil assembly inaccordance with an embodiment of the present invention.

[0014]FIG. 1b is a top plan view of the inductive coil assembly.

[0015]FIG. 1c is a front plan view of the inductive coil assembly.

[0016]FIG. 1d is a side elevational view of the inductive coil assembly.

[0017]FIG. 2 is a perspective view of a bobbin in accordance with anembodiment of the present invention.

[0018]FIG. 3 is a top plan view of the bobbin.

[0019]FIG. 4 is a front view of the bobbin.

[0020]FIG. 5 is a right side elevational view of the bobbin.

[0021]FIG. 6 is a perspective view of two mold pieces for use in moldingthe bobbin.

[0022]FIG. 7 is a plan view of the first mold piece.

[0023]FIG. 8 is a plan view of the second mold piece.

[0024]FIG. 9 is a perspective view of an alternative bobbin.

[0025]FIG. 10 is a perspective view of a second alternative bobbin.

[0026]FIG. 11 is a perspective view of a third alternative bobbin.

[0027]FIGS. 12a-d are perspective views of a fourth alternative bobbinshowing the bobbin is different mounting position.

[0028]FIGS. 13a-c are circuit diagrams of alternative multi-axisinductive coil assembly circuits for receiving power from an inductivesource.

[0029]FIG. 14 is a circuit diagram of a multi-axis inductive coilassembly circuit for receiving communication from an inductive source.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0030] An inductive coil assembly 10 manufactured in accordance with anembodiment of the present invention is shown in FIGS. 1a-d. Theinductive coil assembly 10 generally includes three separate coils 12,14 and 16 that are arranged at separate orientations with respect to oneanother. The separate coils 12, 14 and 16 may be electrically connectedto a device through an inductive control circuit. The separate coils 12,14 and 16 may be wrapped around a one-piece bobbin 20 that facilitatesthe manufacture and assembly of the present invention. Although thepresent invention is described in connection with a three-coilembodiment, the number of coils may vary.

[0031] As noted above, the inductive coil assembly 10 includes a bobbin20 for supporting the various coils 12, 14 and 16. In one embodiment,the bobbin 20 is a one-piece structure that is specially designed foreasy manufacture and easy assembly of the inductive coil assembly 10. Inthe illustrated embodiment, the bobbin 20 is configured to support threeseparate coils 12, 14 and 16 arranged substantially orthogonally withrespect to one another. More specifically, the bobbin 20 accommodatesthree coils 12, 14 and 16, one oriented about each of the x, y and zaxes of a Cartesian three-dimensional coordinate system. In theillustrated embodiment, the bobbin 20 also includes a pair of electricalpins 62 a-b, 64 a-b and 66 a-b for electrically connecting opposite endsof each coil to a circuit board (not shown).

[0032] To facilitate manufacture, the bobbin 20 may be designed to bemolded with a two-piece mold requiring no moving slides, moving pins orother complex moving mold elements. As show in FIGS. 3, 4 and 5, this isachieved by the unique configuration of the bobbin 20, which does notinclude any undercuts that would prevent removal of the molded part fromthe mold. FIG. 3 shows a top view of the bobbin 20, which is in adirection parallel to the direction in which the mold opens and closes.FIG. 4 shows a front view the bobbin 20, which is in a directionperpendicular to the direction in which the mold opens and closes.Finally, FIG. 5 shows a side elevations view of the bobbin 20, whichlike FIG.4 is in a direction that is perpendicular to the direction inwhich the mold opens and closes. Referring now to FIG. 2, the bobbin 20generally defines three separate spools 22, 24 and 26, one for each ofthe three coils 12, 14 and 16. The first spool 22 includes a core 28 anda pair of opposed guide walls 30 a-b that define a somewhat oval channelto receive wire. The core 28 defines an opening 29. The first coil 12 iswrapped around the core 28 with the guide walls 30 a-b providing awrapping guide and helping to retain the coil 12. The second spool 24 isdefined by a second core 34 and a second pair of guide walls 32 a-b. Thesecond core 34 may be convex to provide a round surface for receivingthe second coil 14. Alternatively, the core 34 can be partially definedby the outer surfaces of the guide walls 30 a-b of the first spool 22.The second pair of guide walls 32 a-b extends perpendicularly to theguide walls 30 a-b of the first spool 22. The second coil 14 is wrappedaround the second core 34 with the guide walls 32 a-b providing awrapping guide and helping to retain the coil 14. The third spool 26 isdefined by a third core 40, inner guide segments 36 a-h and outer guidesegments 38 a-d. The outer surfaces of the core 40 may be convex toprovide a curved surface for receiving the coil 16. Alternatively, thecore 40 can be partially defined by the outer surfaces of the guidewalls 32 a-b of the second spool 24. The inner guide segments 36 a-hextend along a common plane to cooperatively define a first wiring guidefor the third coil 16. Similarly, the outer guide segments 38 a-d extendalong a common plane to cooperatively define a second wiring guide forthe third coil 16. As can be seen, the inner guide segments 36 a-h donot overlap the outer guide segments 38 a-d along the direction of theaxis of the spool 26.

[0033]FIG. 6 is a perspective view showing the two mold pieces 100 and102 in an open position. The mold pieces 100 and 102 close together in aconventional manner to cooperatively define a mold cavity in the shapeof the bobbin 20. FIG. 6 illustrates the mold contours, thereby showinghow the two mold pieces 100 and 102 cooperate to define a single bobbin20 three separate spools 22, 24 and 26 without the need for movingslide, moving pins, moving cores or other moving mold components. Ingeneral, the first mold piece 100 forms the inner surfaces of the bobbin20 and the second mold piece 102 forms the outer surfaces. Referring toFIGS. 6-8, the first mold piece 100 includes various contours thatcontribute to the shape of the first spool 22, including generallyarcuate recesses 104 a-b to cooperatively form the inner surfaces of thefirst core 28, block 106 to form an opening in core 28 (primarily tosave in weight and material), and generally arcuate channels 108 a-b toform the inner surfaces of the guide walls 30 a-b. With regard to thesecond spool 24, the first mold piece 100 defines generally arcuaterecess 110 to form the inner surfaces of the second core 34 andgenerally arcuate channels 112 a-b to form the inner surfaces of theguide walls 32 a-b. With regard to the third spool 26, the first moldpiece 100 defines channel segments 114 a-d to form the inner surfaces ofthe third core 34, recesses 116 a-d to form the inner surfaces of outerguide segments 38 a-d, and recesses 118 a-d to receive protrusions130a-d of the second mold piece 102 and form the inner surfaces of innerguide segments 36 a-d. The first mold piece 100 also defines a pair ofrecesses 120 a-b which receives protrusions 132 a-b and forms the innersurfaces of inner guide segments 36 e-h.

[0034] The second mold piece 102 defines the outer surfaces of the threespools 22, 24 and 26. With regard to spool 22, the second mold piece 102defines a generally arcuate recess 122 which forms the outer surfaces ofcore 28 and generally arcuate channels 124 a-b which form the outersurfaces of guide walls 30 a-b. With regard to spool 24, the second moldpiece 102 defines a generally arcuate recess 126 which forms the outersurface of core 34 and generally arcuate channels 128 a-b which form theouter surfaces of guide walls 32 a-b. With regard to spool 26, thesecond mold piece includes a set of four protrusion 130 a-d that extendinto recesses 118 a-d in the first mold piece 100 and a pair ofprotrusions 132 a-b that extend into recesses 120 a-b. Each protrusion130 a-d defines a recess 134 a-d to form the outer surfaces of innerguide segments 36 a-d. Similarly, each protrusion 132 a-b defines a pairof recesses 134 e-h to form the outer surfaces of inner guide segments36 e-h.

[0035] Although the above described embodiment includes a single bobbin20 for all three coils. The inductive coil assembly may includealternative constructions. For example, an alternative inductive coilassembly may include a separate, single-spool bobbin for each coil. Thethree-coil bobbin assembly 320 illustrated in FIG. 9 includes threeseparate bobbins 320 a-c that have different diameters and are fittedone inside the other. Given that the power induced in a secondary coilis proportional to the diameter of the coil, the use of differentlysized bobbins may result in an imbalance in the power supplied to eachsecondary coil. In applications where it is desirable to balance thepower induced in the different coils, additional turns of wire can beadded to the smaller spools 322, 324 and 326, with the precise number ofadditional turns added to each smaller bobbin depending primarily on itssize. For example, if the coil in the outermost bobbin 320 c includesseven turns, it may be desirable to include eight turns on the coil inthe middle bobbin 320 b and nine turns on the coil in the innermostbobbin 320 c. In another alternative embodiment illustrated in FIG. 10,the inductive coil assembly 410 may include three separate bobbins 420a-c that are positioned adjacent to one another, rather than nestedinside of one another. Alternatively, the inductive coil assembly mayinclude a spherical bobbin (not shown), with each coil being wrappedabout the spherical bobbin at the desired location and in the desiredorientation, for example, about the x, y and z axes. This embodimentreduces the differences in the diameters of the three secondaries,thereby improving the balance of the coils. In yet another alternativeembodiment, the inductive coil assembly may include three separate,unconnected bobbins that can be place at varied locations. In thisembodiment, the bobbins may be a simple annular spool or may include aunique shape that permits them to be easily mounted at different angles.An inductive coil with a unique multi-position bobbin 520 is shown inFIGS. 11 and 12a-d. This bobbin 520 generally includes a single spool522, a pair of guide walls 524 a-b and a mounting arm 550. Theconfiguration of the various components permits the bobbin 520 to bemounted in various orientations, for example, to a circuit board. Themounting arm 550 generally includes two arm segments 552 and 554. In theillustrated embodiment, the first arm segment 552 includes a pair ofrails 556 a-b. Rail 556 a is disposed at the end of the first armsegment 552. The rails 556 a-b may be triangular in cross section. Forexample, rail 556 a may extending at 45 degrees with respect to the axisof the spool. To facilitate mounting of the bobbin 520 at an angle,guide wall 524 a may terminate in a common plane with the mounting arm550, and more specifically with the end of the first arm segment 552.The angle of this common plane is set at the desired mounting angle. Forexample, in the illustrated embodiment, the common plane extends at 45degrees from the axis of the spool 522. To facilitate mounting, guidewall 524 a may be chamfered along the common plane, for example, at 45degrees. In this way, the angled surface of rail 556 a and the chamferededge of guide wall 524 a extend along the common plane to provide a firmstructure for supporting the bobbin 520 at a 45 degree angle. The bobbin520 also includes two sets of electrical pins 540 a-b and 542 a-b thatfunction as alternative electrical connections or alternative mountingpins or both depending on the orientation of the bobbin 520. FIG. 12ashows bobbin 520 mounted to a circuit board at a 45 degree angle. FIG.12b shows the bobbin 520 mounted to a circuit board in a verticalposition extending partially through the board. FIG. 12c shows thebobbin 520 mounted to a circuit board in a vertical position fully above(or below) the board. And finally, FIG. 12d shows the bobbin 520 mountedto a circuit board in a horizontal position.

[0036] In a further embodiment (not shown), the bobbin may include twoseparately manufactured pieces that are assembled to form the completebobbin. For example, the bobbin may be formed from two identical moldpieces, with the two mold pieces corresponding to the opposite halves ofbobbin 20 when divided by a plane extending parallel to and mid-waybetween the inner and outer guide segments 36 a-h and 38 a-d,respectively. Because this alternative bobbin is formed in two separatepieces, the staggered inner and outer guide segments 36 a-h and 38 a-d,respectively, can be replaced by continuous guide walls. The continuousguide wall can be placed at the mold parting line to facilitatemanufacture. In this embodiment, the two bobbin pieces may be separatelymolded and then welded, glued or otherwise intersecured to form thecompleted bobbin. As an alternative to conventional adhesives orfasteners, the two bobbin pieces may be held together by the coilwindings. For example, the two pieces may be configured so that thefirst coil is wound in a direction that holds the two bobbin piecestogether.

[0037] The inductive coil assembly 10 of the present invention can beincorporated into essentially any inductively power device to improvepower transfer in various orientations of the device within the magneticfield. For example, a cell phone (not shown), personal digital assistant(not shown), notepad computer (not shown), digital music player (notshown) or electronic gaming device (not shown) can be provided with aninductively powered battery charger having a secondary with multiplecoils, such as inductive coil assembly 10. In this context, the cellphone, personal digital assistant, notepad computer, digital musicplayer or electronic gaming device can be placed randomly within themagnetic field created by a primary coil without concern for itsorientation because the inductive coil assembly 10 will be able toobtain sufficient power to charge the device in any orientation.

[0038]FIGS. 13a-c show circuit diagrams for three embodiments of theinductive coil assembly. FIG. 13a illustrates a circuit 680 thatprovides DC power from three separate coils 672 a-c. As shown, the threecoils 672 a-c are connected in parallel to the load, a capacitor 674 a-cis connected in series between each coil 672 a-c and the load. In thisembodiment, the value of each capacitor 674 a-c and each diode 676 a-cis selected to provide a resonant circuit for the load-side of thecircuit. Accordingly, their values may be dependent on thecharacteristics of the load (not shown). This circuit 680 combines thepower induced within each of the coils using the capacitors to provideresonance with the load, and diodes 676 a-c rectifying the voltageoutput from circuit 680. Alternatively, diodes 676 a-c can be eliminatedfrom the circuit 680 to provide AC power to the load.

[0039]FIG. 13b illustrates a half wave rectifier circuit 680′ thatprovides DC power from three separate coils 672 a-c′. As shown, thethree coils 672 a-c′ are connected in parallel to the load through anarrangement of diodes 676 a-f′ connected in series between each coil 672a-c′ and the load. In this embodiment, the value of each diode 676 a-f′is determined based primarily on the characteristics of the load.Additionally, a capacitor 674 a-c′ is connected in series between oneside of the coil 672 a-c′ and the corresponding diodes 676 a-f′. Thevalue of each capacitor 674 a-c′ is also determined based primarily onthe characteristics of the load. This circuit 680′ combines the powerinduced within each of the coils using the capacitors to provideresonance with the load, and diodes 676 a-f′ rectifying the voltageoutput from the circuit 680′.

[0040]FIG. 13c illustrates a full wave rectifier circuit 680″ thatprovides DC power from three separate coils 672 a-c″. As shown, thethree coils 672 a-c″ are connected in parallel to the load through anarrangement of diodes 676 a-l″ is connected in series between each coil672 a-c″ and the load. In this embodiment, the value of each diode 676a-l″ is determined based primarily on the characteristics of the load.Additionally, a capacitor 674 a-c″ is connected in series between oneside of the coil 672 a-c″ and the corresponding diodes 676 a-c″ anddiodes 676 j-l″. The value of each capacitor 674 a-c″ is determinedbased primarily on the characteristics of the load. All three of thesecircuits 680, 680′ and 680″ perform the function of providing DC power.Circuit 680 is likely the least expensive design, while circuit 680″provides the best control over the DC output, for example, circuit 680″likely provide less fluctuation in the output compared to the other twoembodiments.

[0041] In another alternative, the inductive coil assembly can also beused to inductively transfer communications. In one embodiment, this canbe achieved using an inductive coil assembly that is essentiallyidentical to the inductive coil assembly 10 described above. In thisembodiment, the received communications signals are carried on the powersignal. There are a variety of existing communications protocols usedwith inductive communications to permit the overlay of communicationsand power. In another embodiment, a second set of coils are used toprovide communications. The second set of coils can be formed on thesame bobbin used for the power coils, for example, by wrapping aseparate communication coil on top of each power coil. Thecommunications coils may require only one or two turns of wire.Alternatively, a second bobbin can be used for the communications coils.The inductive coil assembly of the present invention can readily be usedwith a wide variety of conventional inductive communications systems.For example, FIG. 14 is a circuit diagram representing a conventionalcommunications circuit for use in applications where the communicationssignals are separate from the power signals. This circuit enables thesimple inductive exchange of communications between a primary and asecondary with a multi-axis inductive coil assembly. The coils 672 a-c″′are connected in series to the transceiver 690 a-b″′, which isrepresented by RX line 690 a″′ and TX line 690 b″′. The circuit 670″′may include conventional filtering and conditioning components thatlimit current and increase the signal to noise ratio, thereby improvingthe performance of the circuit. For example, in the illustrated circuit,the RX line 690 b″′ may be include resistor 692″′ and capacitor 694″′ toreduce frequency spikes and noise to increase the signal to noise ratio.Similarly, the circuit 670″′ may include resistor 696″′ and capacitors686″′ and 688″″ to filter and condition the incoming and outgoingsignals. This circuit 670″′ combines the communication signals inducedwithin each of the coils 672 a-c″′ and applies them to RX line 690 b″′or applies the signals returned from TX line 690 a″′ to the coils 672a-c″′ to inductively transmit communication signals. The presentinvention may also be implemented using any of a wide variety ofconventional circuits, including circuits in which the coils 672 a-c″′are in a parallel relationship. As noted above, the present invention isalso well suited for use in applications where the communicationssignals are carried by the power signals.

[0042] Although described primarily in the context of a secondary coilassembly, which inductively receives power or communications or bothfrom an inductive primary, the present invention may also be used as amulti-axis primary coil. In this embodiment (not shown), the differentcoils generate magnetic fields at different orientations. A singlesecondary coil is then capable of receiving power or communication orboth at different orientations with respect to the primary, for example,as the secondary coil is sufficiently aligned with any one of themagnetic fields generated by the multi-coil inductive primary.

[0043] The above description is that of a preferred embodiment of theinvention. Various alterations and changes can be made without departingfrom the spirit and broader aspects of the invention as defined in theappended claims, which are to be interpreted in accordance with theprinciples of patent law including the doctrine of equivalents. Anyreference to claim elements in the singular, for example, using thearticles “a,” “an,” “the” or “said,” is not to be construed as limitingthe element to the singular.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. An inductive coilassembly comprising: a first coil arranged at a first orientation toreceive at least one of inductively transmitted power and inductivelytransmitted communications; a second coil arranged at a secondorientation to receive at least one of inductively transmitted power andinductively transmitted communications, said first orientation beingdifferent from said second orientation; and wherein said first coil andsaid second coil are electrically connectable to an electronic device,whereby the electronic device receives at least one of power andcommunication from at least one of said first coil and said second coil.2. The inductive coil assembly of claim 1 further comprising a thirdcoil at a third orientation to receive at least one of the inductivelytransmitted power and inductively transmitted communications, said thirdorientation being different from said first orientation and said secondorientation.
 3. The inductive coil assembly of claim 2 wherein saidfirst orientation is substantially perpendicular to said secondorientation.
 4. The inductive coil assembly of claim 3 wherein saidsecond orientation is substantially perpendicular to said thirdorientation; and said third orientation is substantially perpendicularto said first orientation.
 5. The inductive coil assembly of claim 4further including a bobbin; and wherein each of said first coil, saidsecond coil, and said third coil are wrapped about said bobbin.
 6. Theinductive coil assembly of claim 5 wherein said bobbin include a firstspool, a second spool and a third spool.
 7. The inductive coil assemblyof claim 6 wherein said first spool, said second spool and said thirdspool are integral with one another.
 8. The inductive coil assembly ofclaim 1 further including a rectifying means for rectifying andcombining an alternative current induced in each said coils, saidrectifying means being electrically connected with each of said coils,whereby a resultant direct current is provided.
 9. An inductive coilassembly comprising: a first coil arranged at a first orientation forinductive transmission of at least one of power and communications; asecond coil arranged at a second orientation for inductive transmissionof at least one of power and communications, said first orientationbeing different from said second orientation; and an electronic circuitelectrically connected to said first coil and said second coil, saidelectronic circuit providing at least one of power and communication tosaid first coil and said second coil, whereby said first coil and saidsecond coil induce magnetic fields at distinct orientations.
 10. Theinductive coil assembly of claim 9 further comprising a third coil at athird orientation for inductive reception or inductive transmission ofat least one of power and communications, said first orientation beingsubstantially perpendicular to said second orientation and said thirdorientation, said second orientation being substantially perpendicularto said third orientation.
 11. An inductively powered device comprising:an electric load requiring electric power for operation; an inductivecoil assembly having a plurality of coils, each of said coils arrangedat a distinct physical orientation, each of said coils electricallyconnected to said load; a rectifier for rectifying an alternativecurrent induced in said coils, said rectifying means being electricallyconnected with each of said coils, whereby direct current is applied tosaid load.
 12. The inductive coil assembly of claim 11 furthercomprising a third coil at a third orientation, said third orientationbeing different from said first orientation and said second orientation.13. The inductive coil assembly of claim 12 wherein said firstorientation is substantially perpendicular to said second orientation.14. The inductive coil assembly of claim 13 wherein said secondorientation is substantially perpendicular to said third orientation;and said third orientation is substantially perpendicular to said firstorientation.
 15. The inductive coil assembly of claim 14 furtherincluding a bobbin; and wherein each of said first coil, said secondcoil, and said third coil are wrapped about said bobbin.
 16. Theinductive coil assembly of claim 15 wherein said bobbin include a firstspool, a second spool and a third spool.
 17. The inductive coil assemblyof claim 16 wherein said first spool, said second spool and said thirdspool are integral with one another.
 18. A secondary for an inductivelypowered device comprising: a first coil arranged at a first angularorientation; a second coil arranged at a second angular orientation,said first angular orientation being different from said secondorientation; and circuit means for electrically connecting said firstcoil and said second coil with a common load.
 19. The secondary of claim18 wherein said first angular orientation and said second angularorientation are about ninety degrees apart.
 20. The secondary of claim19 further comprising a third coil arranged at a third angularorientation, said third angular orientation being different from saidfirst orientation and said second orientation.
 21. The secondary ofclaim 20 wherein said first angular orientation, said second angularorientation and said third angular orientation are each about ninetydegrees apart from one another.
 22. The secondary of claim 21 furthercomprising a capacitor connected in series between said load and each ofsaid first coil, said second coil and said third coil.
 23. The secondaryof claim 20 wherein said first coil, said second coil and said thirdcoil are electrically connected in a half-bridge arrangement with adiode connected in series between said load and each of said first coil,said second coil and said third coil.
 24. The secondary of claim 20wherein said first coil, said second coil and said third coil areelectrically connected in a full bridge arrangement with a pair ofdiodes connected in series between said load and opposite sides of eachof said first coil, said second coil and said third coil.
 25. Thesecondary of claim 20 wherein said first coil, said second coil and saidthird coil are wrapped about a common bobbin.
 26. The secondary of claim20 wherein said first coil, said second coil and said third coil arewrapped about a common substantially spherical bobbin.
 27. The secondaryof claim 20 wherein said first coil is wrapped about a first bobbin,said second coil is wrapped about a second bobbin and said third coil iswrapped about a third bobbin.
 28. The secondary of claim 27 wherein saidfirst bobbin is fitted within said second bobbin and said second bobbinis fitted within said third bobbin.
 29. The secondary of claim 27wherein said first bobbin has a first diameter, said second bobbin has asecond diameter and said third bobbin has a third diameter, said firstdiameter being smaller than said second diameter, said second diameterbeing smaller than said third diameter; and wherein said first coilincludes a greater number of turns than said second coil and said secondcoil includes a greater number of turns than said third coil.
 30. Thesecondary of claim 18 wherein said first coil and said second coil areconnected in parallel with said common load.
 31. The secondary of claim18 wherein said first coil and said second coil are connected in serieswith said common load.
 32. An inductively powered device comprising: aload; and a secondary electrically connected to said load, saidsecondary including a first coil electrically connected with said loadand a second coil electrically connected with said load, said first coilarranged at a first angular orientation, said second coil arranged at asecond angular orientation different from said first angularorientation.
 33. The secondary of claim 32 wherein said first angularorientation and said second angular orientation are about ninety degreesapart.
 34. The secondary of claim 33 further comprising a third coilarranged at a third angular orientation, said third angular orientationbeing different from said first orientation and said second orientation.35. The secondary of claim 34 wherein said first angular orientation,said second angular orientation and said third angular orientation areeach about ninety degrees apart from one another.
 36. The secondary ofclaim 34 further comprising a capacitor connected in series between saidload and each of said first coil, said second coil and said third coil.37. The secondary of claim 34 wherein said first coil, said second coiland said third coil are electrically connected in a half-bridgearrangement with a diode connected in series between said load and eachof said first coil, said second coil and said third coil.
 38. Thesecondary of claim 34 wherein said first coil, said second coil and saidthird coil are electrically connected in a full bridge arrangement witha pair of diodes connected in series between said load and oppositesides of each of said first coil, said second coil and said third coil.39. The secondary of claim 34 wherein said first coil, said second coiland said third coil are wrapped about a common bobbin.
 40. The secondaryof claim 34 wherein said first coil, said second coil and said thirdcoil are wrapped about a common substantially spherical bobbin.
 41. Thesecondary of claim 34 wherein said first coil is wrapped about a firstbobbin, said second coil is wrapped about a second bobbin and said thirdcoil is wrapped about a third bobbin.
 42. The secondary of claim 41wherein said first bobbin is fitted within said second bobbin and saidsecond bobbin is fitted within said third bobbin.
 43. The secondary ofclaim 42 wherein said first bobbin has a first diameter, said secondbobbin has a second diameter and said third bobbin has a third diameter,said first diameter being smaller than said second diameter, said seconddiameter being smaller than said third diameter; and wherein said firstcoil includes a greater number of turns than said second coil and saidsecond coil includes a greater number of turns than said third coil. 44.The secondary of claim 34 wherein said first coil, said second coil andsaid third coil share a common origin.
 45. The secondary of claim 34wherein said first coil is nested within said second coil and saidsecond coil is nested within said third coil.
 46. An inductive coilassembly comprising: first, second and third coils; and a one-piecebobbin defining three spools for receiving said first, second and thirdcoils, said first spool having an axis extending in a first direction,said second spool having an axis extending in a second directionsubstantially perpendicular to the first direction, said third spoolhaving an axis extending in a third direction substantiallyperpendicular to both said first direction and said second direction,said third spool including a plurality of inner guides and a pluralityof outer guides, said inner guides and said outer guides being in anon-overlapping disposition in said third direction.
 47. The inductivecoil assembly of claim 46 wherein said first spool includes a pair ofguide walls extending in a direction substantially parallel to saidthird direction and said second spool including a pair of guide wallsextending in a direction substantially parallel to said third direction.48. The inductive coil assembly of claim 47 wherein said first coilincludes a greater number of turns of wire than said second coil andsaid second coil of wire includes a greater number of turns of wire thansaid third coil.
 49. A bobbin for a three-axis inductive coil assembly,manufactured by a process including the steps of: providing a first moldpiece; providing a second mold piece; closing the first mold piece andthe second mold piece together to cooperatively define a mold cavity,the mold cavity defining a first spool having an axis extendingsubstantially perpendicularly to a direction in which a molded part isremoved from the mold, the mold cavity further defining a second spoolhaving an axis extending substantially perpendicularly to the directionin which a molded part is removed from the mold, the mold cavity furtherdefining a third spool having an axis extending substantially in thedirection in which a molded part is removed from the mold, the thirdspool including a plurality of inner guides extending substantiallyalong a first plane and a plurality of outer guides extendingsubstantially along a second plane, the first plane being spaced apartfrom the second substantially in the direction in which a molded part isremoved from the mold, the plurality of inner guides being innon-overlapping relationship with the plurality of outer guides in thedirection in which a molded part is removed from the mold; injectingmaterial into the mold cavity; and removing the molded part from thecavity.
 50. A bobbin for an inductive coil assembly comprising: a spoolhaving an axis and a pair of guide walls disposed on opposite sides ofsaid spool, said guide walls extending substantially perpendicularly tosaid axis; and a mounting arm extending from a first one of said guidewalls, said mounting arm having a free end terminating in a first commonplane with at least one of said guide walls, said first common planeextending parallel to said axis.
 51. The bobbin of claim 50 wherein saidmounting arm includes a first segment extending substantiallyperpendicularly to said axis and a second segment extending at an anglefrom said first segment.
 52. The bobbin of claim 51 wherein said secondsegment extends substantially perpendicularly to said axis.
 53. Thebobbin of claim 52 wherein a portion of said first guide wall and aportion of said mounting arm terminate in a second common plane.
 54. Thebobbin of claim 53 wherein said second common plane extends atapproximately 45 degrees with respect to said axis.
 55. An inductivecoil assembly comprising: a first coil arranged at a first orientationto receive at least one of inductively transmitted power and inductivelytransmitted communications; a second coil arranged at a secondorientation to receive at least one of inductively transmitted power andinductively transmitted communications, said first orientation beingdifferent from said second orientation; and an electronic deviceelectrically connected to said first coil and said second coil, saidelectronic device receiving at least one of power and communication fromat least one of said first coil and said second coil.